Regulating apparatus for refrigerating-compartments.



No. 716,480. Patented Dec. 23, 1902. n. w. noLuns.

BEGULATING APPARATUS FOR BEFBIGEBATING GOMPARTMENTS.

\ (Application filed Aug. 12, 1901.)-

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Patnted Dec. 23, i902. B. W. RULLlNS.

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I No. 6,480.

BEGULATING APPAB FOR BEFBIGERA (Application filed Aug. 12, 1901.)

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Patented Dec. 23, I902; R. W. HOLLINS.

REGULATING APPARATUS FOR REFB'IGERATING COMPARTMENTS.

\ (Application filed Aug. 12, 1901.)

3 Sheets-Sheet 3.

(N0 Model.)

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UNrrED STATES PATENT OFFICE.

ROBERT W. ROLLINS, OF HARTFORD, CONNECTICUT.

REGULATING APPARATUS FOR REFRIGERATING-COMPARTMENTS.

SPECIFICATION forming part of Letters Patent No. 716,480, dated December23, 1902.

Application filed August 12, 1901. Serial No. 71,730. (No modeLl To allwhom it may concern:

Be it known that 1, ROBERT W. RoLLINs, a citizen of the United States,residing in Hartford, in the county of Hartford and State ofConnecticut, have invented certain new and useful Improvements inRegulating Appara tus for RefrigeratingCompartments,of which thefollowing is a specification My invention relates to regulatingapparatus for refrigerating-compartments in which it may be desired toproduce ice artificially or to store food and other materials forpurposes of preservation.

Mainly the object of my invention is the provision in a refrigeratingplant of automatic regulating devices which will serve to control theadmission of refrigerating liquid to the coils or otherexpansion-chambers within the refrigeratingcompartments in which saidliquid vaporizes to lower the temperature.

A further object of the invention is theprovision of an automaticregulator operated by back pressure within the expansion-coils andserving when actuated in this manner to close the inlet valve or valves.

A further object of the invention is the provision of means for shuttingoff the watersupply from the main or other source of pressure, andthereby saving waste of water used for condensing the anhydrousammonia-gas or other liquid employed when the conditions are such as towarrant it.

A further object of the invention is the provision of electrical devicescontrolled by a thermostat or thermostats and also by an automaticback-pressure regulator for closing the inlet-valve to theexpansion-chamber, said regulator also controlling a valve leading tothe pipe which supplies water to the chamber in which thecondensing-coil is located.

Referring to the accompanying drawings, Figure 1 is a perspectiverepresentation of a refrigerating plant involving the details of myinvention. Fig. 2 is a side elevation, detached, of an automaticregulator operative by back pressure within the expansion-coils and pipesystem. Fig. 3 is a view of a modified form of said regulator. Fig. 4 isa longitudinal vertical section ofa valve-chamber connected with theexpansion coil or chamher. Fig. 5 is a transverse vertical section ofsaid valve-chamber, showing the magnets in elevation. Figs. 6, 7, and 8are detail views of the means employed for opening and closing theconduit leading from the pump for supplying water to the compartment inwhich the vapor-condensing coil is located. Figs. 9 and 10 arerespectively plan and side views of a valve employed in a chamber of theconduit leading to the pump.

Like numerals designate similar parts throughout the several views.

Referring to the drawings, the numerals 5 and 5' designaterefrigerating-compartments of any desired kind, form, size, orproportions,and the numerals 6 and 6', respectively, refrigerating orexpansion coils, (hereinafter termed eXpansion-chambers,) which arelocated in the illustrations given at the tops of the compartments,although they may be differently disposed without departure from theinvention. These coils are shown as horizontally arranged; but this isim material, for they may be disposed at an angle or vertically, ifdesired. Furthermore, the coils are simply-illustrative of any desiredkind of expansion-chamber suitable for accomplishing the purpose, and itis distinctly to be understood that the invention is not limited to saidcoils, for other devices may be substituted therefor without departuretherefrom.

Connected with a portion of the coil or expansion-chamber 6 is a pipe 7,and with a similar portion of the coilor expansion-chamber 6 is a pipe7, and these pipes are utilized for the delivery of the volatilerefrigerating agent employedforinstance,anhydrous ammonia-to said coils.This liquid is caused to enter the coils or expansion-chambers underforced pressure from a tank or receiver 8 or other receptacle, and theliquid may be of any desired kind proper for accomplishingrefrigerating-work.

The ammonia-receiver S is connected by a pipe 9 with a pipe 10, to whichbranch pipes 12 and 13 are coupled, as shown in Fig. 1, and these branchpipes are united to short sections 12 13, respectively, to whichvalvechambers, (designated in a general way by 14 14,) are connected,the opposite sides of said valvechambers being united to the inletpipes7 and 7.

Connected to the outlet extensions 15 15' of the coils constituting theexpansion-chambers 6 and 6 are branch exhaust-pipes 16 16, which areunited by a T or other suitable coupling to an exhaust-pipe 17. Adjacentto one end this pipe 17 connects with a branch 18, coupled to a pipe 19,leading to a pump 20 of ordinary construction, and leading from saidpump 20 is a branch 21, coupled to an extension 22 of a condensing-coil22, said coil having another extension 22 which delivers the liquid fromthe coil to an ammonia-receiver 8. This coil 22 is located in a tank 23,to which water is supplied by a pipe 24, having a connection 25 to astreet service-main, (not shoWn,) and passing through the wall of tank23 is an overflow-pipe 26, which will prevent the water in said tankfrom rising above a certain level.

Within each compartment 5 5 is placed a thermostat 27 27, respectively,and these thermostats may be of any desired kind, that in compartment 5being of how form, with a leg 2'7 adapted when the thermostat iseffected by rising temperature and expands to engage a contact-point,andthereby establish an electrical circuit for energizing the magnets ofthe inlet-valve hereinafter described, and that in compartment 5 beingof the type in which a column of mercury 27 makes connection with aterminal of one of the wires leading to the magnets for actuating theValve in chamber 14. Any kind of thermostat may be substituted foreither of those shown, provided it is suitable for the purpose desired.

Coming now to the valve-chambers 14 14, connecting the pipes 7 and 12and 7 and 13, each of said chambers is alike and consists of a casing28, secured by screws 29 to a partition or other support 30. Projectingfrom the casing is a non-frost-collecting shelf 31, the paper-pulpproduct known as hard fiber having been found in practice to prevent theaccumulation of frost which always impairs the efficiency of the magnetshereinafter described. Upon this fibrous shelf 31 is a base 32,supporting a pair of solenoid or other suitable magnets 33, the cores 34of which are united by an armature 35. Within the valve chamber 14 areperforated lugs 36, and at one side of said lugs is a tubular projection37, closed at one end and having a port 37 for delivering the fluidemployed from the valvechamber, to which it is fed, to theexpansionchamber 6 by the inlet-pipe 7, said liquid entering thevalve-chamber by pipe 12, above described. Fitted for reciprocatorymovement in the perforated lugs 36 is a needlevalve 38, and surroundingthe stem of said valve between the lugs is a coiled spring 39, whichbears at one end against the under side of one of the lugs and at itsopposite end against a pin 40 on the valve-stem and tends normally toclose the valve. At the end opposite to its valve portion 38 the stem 38is provided with a head 38 for accomplishing a purpose hereinafterdescribed.

J ournaled in bearings 41 of the chamber 14 is a rock-shaft 42, andsecured to said rockshaft within the valve-chamber is a curved arm orwiper 43, which bears against the under side of the valve-stem head 38This rock-shaft passes through a bushing 44 to the exterior of thecasing 28, and to its outer end is secured a lever 45, connected by alink 46 with an armature or cross-bar 35. Passing through a bracket 47of the chamber 14 is a screw 48, and connected to said screw and to thelever 45 is a spring 49, which normally tends to lift said lever and itsconnected armature and permit the valve to be closed by the spring 39.Threaded into a part of the casing is a stop-screw 50, carryinga'jam-nut 51, and by adjusting this screw the opening movement of thevalve may be regulated as desired. Connected with the coils of the magnets are wires 52 and 53, wire 52 being attached to a terminal fromcontact-point 28 and wire 53 to a terminal leading to a wire 80,connected to the generator, (see Fig. 1,) and when the temperature risesin the refrigerating-compartment the leg 27 of the thermostat willexpand, engage the contact-point 28, and cause a circuit to beestablished which will energize the magnets 33, thereby causing saidmagnets to actuate the lever 45'and raise the valve 38, thus permittingan inflow of volatile liquid to the expansion-chamber 6. When thetemperature in the refrigeratingcompartment falls, the thermostat willcontract, thereby interrupting the connection and permitting the valve38 to close under the action of spring 39 and shut off the supply ofrefrigerating liquid. In the compartment 5 the action is the same,although a different form of thermostat is shown, and the electricalconnections to said compartment are indicated by the powers of thenumerals above mentioned. Here it may be well to mention that theinvention is not limited to a pair of refrigerating-compartments, forone or any desired number may be employed, as circumstances require.

In apparatus of the class described it frequently happens that thepressure of the va por in the coils varies both above and below thenormal standard, and as it is a desideratum to maintain this pressureconstant, and thereby prevent undue back pressure upon the pump forexhausting the vapor from the expansion-chamber and forcing it into thecondenser, I have devised the following means for accomplishing thispurpose and also for controlling the admission of fiuid to saidexpansion-chamber. Should it happen that all of the thermostats in therefrigerating-compartments are open, it is desirable to save water byshutting off the supply to the tank in which the condenser is mounted,and the valve for accomplishing this result is also controlled by thedevice actuated by a variation in the pressure, as will hereinafter bedescribed.

The suction-pipe' 19 of the pump 20 is carried above the branch 18,extending from the IIO pipe 17, the latter communicating by conduits 1616 and 15 15 with expansion-chambers 6 6', and in this extension of pipe19 is formed a coil 19, (although this may be omitted, if desired,) theupper end of which is closed by a T-coupling 54, connected by a shortpipe 55 with another T-coupling 56, communicating with a curved andsubstantially horseshoe-shaped expansible and contractible tube 57. Thistube is extremely sensitive to variations in pressure and at its freeend carries an insulated plate 58, in which are fitted screws 59 and 60,respectively, the screw 60 being so adjusted that its point is somewhatlower than that of the point of the screw 59. Carried by a plate 61,formed of insulating material and secured to one end of the coupling 56,are cups 62 and 63, respectively, containing mercury or other equivalentconducting fluid. To the screw 60 is connected the terminal of a wire64., leading to the battery or other generator, and to the cup 63 isattached the terminal of a wire 65, leading by branch 65 to the contact28 of thermostat 27 and also leading to contact 28 of thermostat 27,while screw 59 is connected to wire 64, leading from wire 64:, and theterminal of a wire 67 is in engagement with the cup 62. Other suitablecontacts may be substituted for those shown without departure from theinvention. The wires 65 and 65' are connected with the contacts 28 28 ofthe thermostats, as shown in Fig. 1. iVith this construction shouldthere be back pressure such pressure will tend to'straighten or expandthe coil 57, thereby withdrawing the tip of screw 60 from the mercury incup 63 and causing the circuit to be opened between the generator andthe electromagnets, the result being that said magnets will bedeenergized and the valve 38 will be forced to its seat by spring 39, tothereby shut off the supply of refrigerating liquid to the compartments5 5. It is of course to be understood that the pump 20 is constantly atwork and that when the supplypipe is closed by the valve, as juststated, said pump continuing its work will soon cause a reduction ofpressure in the various pipes of the system and in the flexibleexpansion device 57. This will cause the device 57 to curve inward andthrow the contact-point of screw 60 into engagement with the mercury incup 63, thereby again closing the circuit, energizing the magnets, andreopening the valve or valves in the supply-pipes leading to theexpansion coils or chambers. The wires 64, 64., and 67, connected,respectively, to the screw 59 and cup 62, lead to a pair ofelectromagnets 68, which when energized shut off the supply of waterfrom the pipe 25 to tank 26. The numeral 69 designates a valve-chamberwith which the inlet-pipe 25 is connected, and within this valve-chamberis a disk 70, having a transverse port 70, said disk being connected toa rod or shaft 71, projecting through the head of the valve chamber.Upon this rod or shaft 71 is clamped an arm 72, connected at one side ofits axis with a link 73, which is in turn articulated to a loopshapedsolenoid 74, the arms 74 of which are the cores of the magnets 68.Normally the port 70 of the valve-chamber 69 is in alinement with thepipes 24 and 25, for when the magnets are denergized the connectedsolenoids drop .by gravity and turn said disk to such position asillustrated by dotted lines in Fig. 8. This gravital action may be aidedby a spring or weight, if necessary, and the turning of the valve-disk70 may be regulated by adjustable stops 75 75, the latter being fittedover a bolt or set-screw 76, threaded into the head of thevalve-chamber. The second contact-screw 59 is, as will be observed byFig. 2, so adjusted that its point is higher than that of the point ofscrew 60, and consequently the circuit leading to the magnets 68 foractuating the valve 70 is not closed unless the temperature of all therefrigeratingcompartments is so low that the thermostats are open, inwhich case the pressure in the pipes will cause the free end of theregulator 57 to be carried inward to such an extent that the contact ofscrew 59 described will be made, the circuit will be closed, and themagnets 68 energized to turn the valve and shut off the supply of waterto tank 23.

In Fig. 3 Ihave illustrated a modified form of pressure-actuatedregulator, which may be employed as a substitute for that shown in Fig.2. This form consists ofa casing 80, having a threaded extension whichwill be screwed upon the end of the part 19 of pipe 19. This casing isin two parts 81 and 82, respectively, which are secured together bybolts 83, passing through flanges 84, projecting from the sections ofthe casing. Olamped between these flanges is a diaphragm 85, and securedto the top section of the casing is a standard 86, in which is pivotedan arm of lever 87, the yoke of which is composed, preferably, ofinsulating material, in the ends of which the screws 59 and 60,heretofore described, are mounted. Also secured to the top of the casingis an insulated plate 88, carrying the cups 62 and 63, heretoforedescribed. Threaded within the top plate of the casing 80 is a tubularscrew 89, and passing through said screw is a shank 90, having at itslower end a head which bears against the diaphragm 85, a spring 91serving to force the head 90 downward against the diaphragm. Variationsin the pressure of the refrigerating fluid employed will cause thisdiaphragm to be affected in the same way as the regulator illustrated inFig. 2, and when the pressure varies to a certain extent in the pipesthe lever 87 will be forced downward by the spring 91, thereby causingnormal conditions to be reestablished through the contact of the screw60 with the cup 63. In this modification the screw 59, cup 62, and theirconnections operate in the same manner as similar parts (illustrated inFig.2) for shutting off the water-supply.

In the operation of my improved apparatus should the temperature rise inthe refrigerating-compartments or any of them the thermostat will beaffected and will close the circuit, thereby energizing the magnets andopening the valves,and should the pressure within the expansion-chambersproduce back pressure on the pump the regulator,which is very sensitiveto the slightest variation in the pressure, will act to open thecircuit, thereby deenergizing the magnets, and consequently closing thevalves. So, too, if the temperature is low in the compartments and thethermostats are open the decrease in pressure in the exhaust-pipe systemwill cause the regulator to bring the point 59 into contact with cup 62,thereby closing the circuit and energizing the magnets for actuating thevalve to shut off the water-supply, as above stated.

My invention is not limited to any particular form of regulator forcarrying out these results,and substitutes may be employed for the twoforms shown, if desired.

Any desired kind of magnets may be employed for actuating the valves,andthe invention is not limited to the solenoids shown and described.Variations may also be made in the details of the pipe system and valveswithout departure from the invention.

Having thus described my invention, I claim- 1. In a refrigeratingapparatus, the combination with a compartment, of an expansionchamberwithin the compartment; a valve for regulating the admission ofrefrigerating fluid to the expansion-chamber; an electromagnet capable,upon being energized,of opening the valve; an electric circuit connectedto the electromagnet; a thermostat, operable upon reduction oftemperature within the compartment, to open the circuit ofthe magnet;and means actuated by variation of pressure within the chamber andcapable of opening the circuit upon rise of pressure.

2. In a refrigerating apparatus, the combination with a compartment, ofan expansionchamber within the compartment; an inletvalve for regulatingthe admission of refrigerating liquid to the expansion-chamber; aneleetromagnet for actuating the valve; a thermostat within thecompartment and in circuit with the electromagnet for opening andclosing the circuit upon predetermined falls and rises, respectively oftemperature within the compartment; and means actuated by pressurewithin the chamber and in circuit with the eiectromagnet and with thethermostat for opening and closing the circuit upon predetermined risesand falls, respectively, of pressure within the chamber, theorganization being such that either a fall of temperature or a rise ofpressure will open the circuit and a contemporaneous rise of temperatureand fall of pressure will close the circuit.

3. The combination with a series of refrigerating-compartments, ofexpansion-chambers located in the compartments; a conduit for supplyingfluid to each of the expansionchambers; inlet-valves for the respectivesupply-conduits; electromagnets for severally actuating the valves; athermostat within each of the refrigerating-compartments; common meansconnecting all the chambers; a regulator connected with the connectingmeans and actuated by a variation of pressure in any of theexpansion-chambers; and electrical connections between the regulator andthe magnets for actuating the inlet-valves, the respective thermostatsand the regulator cooperating to control each of the valves through itsrespective magnet.

4. In apparatus of the class specified, the combination withcompartments, of coils located within the compartments; pipes forconveying refrigerating liquid to the coils; valve mechanisms connectedwith the pipes; a thermostatin each compartment; electrical connectionsbetween the thermostat and the valve mechanisms; outlet-pipes for thecoils in the compartments; a pump for withdrawing fluid from all therefrigerating-coils; pipe connections between the pump and the outlet-pipes of all the coils; a regulator actuated by the pressure fromthe coils; and electrical connections between the regulator and each ofthe inlet-valves.

5. The combination with a compartment, of an expansion-chamber in thecompartment; a valve for controlling the supply of liquid to theexpansion-chamber; means for unseating the valve; a thermostat withinthe compartment; a magnet for actuating the valve-unseating means;electrical connections between the thermostat and magnet and operativeby the thermostat; and means actuated by the pressure of therefrigerating medium and operative upon the electrical connectionsbetween the thermostat and magnet.

6. The combination with a compartment, of an expansion-chamber in thecompartment; a valve-chamber in connection with the expansion-chamberand having an inletport; a valve for normally closing the inletport; alever for unseating the valve; a thermostat within the compartment; anelectromagnetic device for actuating the lever; electrical connectionsbetween the thermostat and device and operative by the thermostat; andmeans between the thermostat and magnet actuated by the expansionpressure operative upon the electrical connections.

'7. The combination with a refrigeratingcompartment, of anexpansion-chamber located within the compartment; an inlet-pipe forsupplying refrigerating liquid to the chamber; a valve-chamber connectedto the inletpipe, the chamber having a port; means for supplying fluidto the valve-chamber; a normally closed valve for the port in thevalvechamber; an electromagnet which, when energized, opens the valve; athermostat; electrical connections between the thermostat and themagnet; and means operated by the pressure of the expansion andcooperative with the thermostat for permitting the energization of theelectromagnet.

8. The combination With a refrigeratingcompartment, of anexpansion-chamber located within the compartment; an inlet-pipe forsupplying refrigeratingliqnid to the chamber; avalve-chamber connectedwith the inlet-pipe; a port from the valve-chamber to the inlet-pipe; avalve for the valve-chamber;

means for normally closing the valve; a device for opening the valveagainst the pressure of the closing means; a thermostat within therefrigerating-compartment and affected by change of temperature therein;electromagnetic devices for actuating said device; electricalconnections between the thermostat and the electromagnetic devices; andautomatic means independent of the thermostat and actuated by thepressure of the refrigerating medium for making and breaking theelectrical connections.

9. The combination with a refrigeratingcompartment, of an expansion-coillocated within the compartment; an inlet-pipe for supplyingrefrigerating liquid to the coil; a valve-chamber having a portconnected with the inlet-pipe; means for supplying refrigerating liquidto the valve-chamber; a reciprocatory valve for opening and closing theport; a head upon the valve-stem; a spring for normally closing thevalve; a rock-shaft mounted in the valve-chamber; a cam carried by therock-shaft and adapted to engage the head to open the valve; a leverconnected to the rockshatt; an electromagnet for actuating the lever; athermostat Within the refrigeratingcompartment; electric connectionsbetween the thermostat and the magnet; and a makeand-break deviceactuated by the pressure in the expansion-coil for controlling theconnections between the thermostat and magnet.

10. The combination with a refrigeratingcompartrnent, of anexpansion-chamber within the conpartment; an inlet-pipe for con veyingexpansive fluid to the expansion-chamber; a valve-chamber connected tothe inlet-pipe, and having a port; a valve-stem mounted in guides of thevalve-chamber, and having a head at one end, and shaped to fit the portat the opposite end; a rock-shaft mounted in the valve-chamber; a camcarried by the rockshaft and adapted to engage the head of the stem toactuate the valve in one direction; a spring for actuating the valve inthe opposite direction; a pivoted lever attached to the rock-shaft; apair of electromagnets for actuating the lever in one direction; anadjustable spring independent of the valve-spring for actuating thelever in the opposite direction and for sustaining the Weight of thelever; a thermostat within the refrigeratingcompartment; and an electriccircuit connecting the thermostat with the electromagnets.

11. In a refrigerating system utilizing the expansion of fluid to causereduction of temperatu re, the combination with a plurality ofcompartments, of an expansion-chamber for each compartment; a valve forcontrolling the admission of expansible fluid to each chamber;electrically-operated means for controlling the actuation of each valve;a common exhaust for the chambers; a thermostat for each compartment; anelectrical circuit for each compartment embracing the thermostat andvalve -controlling means; means for withdrawing from the exhaust andcondensing the expanded fluid; means for supplying a flow of fluid tocool the condensed fluid; means actuated by an electric circuitforcontrolling the flow of cooling fluid; means actuated by change ofpressure in the common exhaust for opening all the compartment-circuitsindependently of the thermostats and for closing the same cooperativelywith the respective thermostats and for affecting the circuit foractuating the means for controlling the flow of cooling fluid; and meansfor adjusting the same for opening and closing the former circuit andfor afiecting the latter circuit respectively at different predeterminedpressures.

12. In refrigerating apparatus, the combination, with arefrigerating-compartment, of an expansion-coil located within saidcompartm out; an inlet-pipe leading to said coil; valve mechanismconnected with the inletpipe; a thermostat Within the compartment;electrical connections between said thermostat and the valve mechanism;an exhaustpipe leading from said coil; a pump connected with saidexhaust-pipe; a regulator actuated by a variation in the pressure of thefluid contained in the coil and pipe system; electrical connectionsbetween the regulator and inlet-valve to the coil; a condenser; meansfor supplying Water to said condenser; a valve for controlling thesupply of Water; and electric connections between the regulator and saidvalve.

13. In refrigerating apparatus, the combination, with a series ofcompartments, of an expansion-chamber in each compartment; an inlet-pipeleading to each expansion-chamher; electrically-controlled valvesconnected with the respective inlet-pipes; a pipe for supplying fluidunder pressure to the inletpipes; exhaust-pipes leading from the severalexpansion-chambers; an exhaust system with which the exhaust-pipes areconnected; a pump; a pressure-actuated regulator connected with theexhaust system; and electrical connections between the regulator andeach of the electrically-controlled valves of the inlet-pipes.

14. In refrigerating apparatus, the combination, with a compartment,ofan expansioncoil located in the compartment; a thermostat within thecompartment; an inlet-pipe leading to the expansion-coil; a valve forthe inlet-pipe; electromaguets connected with the thermostat; meanscontrolled by the magnets for actuating the valve; an exhaust-pipeleading from the expansion-coil; a pressurewithin the compartment;electric con nections between the thermostat and the electromagnets; anexhaust-pipe leading from" the expansion-coil; an expansiblepressure-actuated regulator connected with the exhaust-pipe; electricalconnections between the regulator and the valve-actuating magnets; meansfor exhausting the fluid from the'expansion-coil; and a condenser intowhich the fluid is forced.

16. In a refrigerating apparatus, the combination with a compartment, ofan expansionchamber in said compartment; a valve for regulating theadmission of refrigerating liquid to said expansion-chamber; athermostat 'in said compartment; an electromagnet controlled by thethermostat for actuating the valve; a regulator comprising an expansibletube actuated by variations of pressure in the expansion-chamber andconnected with said electromagnet for actuating the valve.

17. In a refrigerating system utilizing the expansion of fluid to causereduction of temperature, the combination with a plurality ofcompartments, of an expansion-chamber for each compartment; a valve forcontrolling the admission of expansible fluid to each chamber;electrically-operated means forcontrolfling the actuation ofeach valve;a common exhaust for the chambers; a thermostat for each compartment; anelectrical circuit for each compartment embracing the thermostat andvalve-controlling means; means for withdrawing from the exhaust, andcondensing, the

expanded fluid; means for supplying a flow of fluid to cool thecondensed fluid; means actuated by an electric circuit for controllingthe flow of cooling fluid; and means actuated by change of pressure inthe common exhaust for opening all the compartment-circuitsindependently'of the thermostats and for closing the same cooperativelywith the respective thermostats, and for aifecting the circuit foractuating the means for controlling the flow of cooling fiuid uponreduction of pressure.

18'; In a refrigerating system utilizing the expansion of fluid to causereduction of temperature, the combination with a plurality ofcompartments, of an expansion-chamber for each compartment; a valve' forcontrolling the admission of expansible fluid to each chamber;electrically-operated means for controlling the actuation of each valve;a common exhaust for the chamber; a thermostat for each compartment; anelectrical circuit for each compartment embracing the thermostat andvalve-controlling means; means for withdrawing from the exhaust, andcondensing, the expanded fluid; means for supplying a flow of fluid tocool the condensed fluid; means actuated by an electric circuit forcontrolling the flow of cooling fluid; a circuitcloser for opening allthe compartment-circuits independently of the thermostats and forclosing the same cooperatively with the respective thermostats; acircuit-closer for opening and closing the circuit for actuating themeans for controlling the flow of cooling fluid; means actuated bychange of pressure in the common exhaust for controllingbothcircuit-closers; means for adjusting the compartment-circuit closerfor opening and closing the circuits at predetermined pressure; andmeans independent thereof for adjusting the flow-circuit closer foropening and closing at predetermined pressures.

ROBERT W. ROLLINS.

Witnesses:

WM. H. BLODGETT, E. M. WILcox.

